1. Field of the Invention
The present invention relates to a gasket.
More particularly, the present invention relates to a gasket which is useful by being used in a battery or the like which is used in an electric vehicle, a fuel cell vehicle, a hybrid vehicle and the like.
2. Description of the Conventional Art
Conventionally, as a gasket for sealing a gap between a case which is a base portion in a lower side of a battery case or the like, and a cover which is a lid portion in an upper side, there has been used an O-ring which has a circular cross section, or a gasket 100 which is obtained by drawing the O-ring in a vertical direction and has a cross sectional shape shown in FIG. 8 (refer to Japanese Unexamined Patent Publication No. 2005-16621).
However, the O-ring has such an advantage that it is simple in a shape so as to be easily produced, and an installing property and a stability after the installation (a seating property) is good, however, has such a disadvantage that a pressing crack tends to be caused at a high compressing time, and a high reaction force is generated.
Accordingly, there is brought about a problem that it can not be used at a position in which a gap greatly fluctuates, and a position in which a material of a case and a cover corresponding to the other end member to be attached is weak, and a width of the O-ring can not help but being larger in a compressed state (a set state) since it is used by compressing a circular cross section. Therefore, there is caused a problem that it can not be used in the case that an installation space is narrow, and a case that a high compression is necessary in comparison with an installation width.
Further, a gasket 100 having a cross sectional shape shown in FIG. 8 can expect an effect of lowering the pressing crack at a time of the high compression and the reaction force to some extent in comparison with the O-ring having a simple shape, however, not only it is impossible to achieve a low reaction force which can be sufficiently satisfied, but also it can not help but being used as a shape of being installed into a groove 210 which is provided in a case 200 as shown in FIG. 8 since a seating property is not good.
Further, it has been impossible to employ an aspect that a bolt hole for fixing the case and the cover is provided in the gasket 100 itself, for making the installation space narrow.